For example, an image, in which a virtual image other than a captured image is superimposed on a captured image of a camera, is called an augmented reality (AR) image and has recently been used in various fields.
In particular, in recent years, portable terminals, such as a smartphone having a camera function and a display as well as a communication function, have been widespread, and applications that apply an AR image to such a smartphone are widely used.
As one example of use of an AR image, there is the following example.
When a certain object is captured by using, for example, a camera function of a portable terminal such as a smartphone, object information, for example, a marker such as a cyber-code printed on the captured object, is identified, a virtual image such as a character or a person selected based on the identified marker is superimposedly displayed on the captured image, and a sound is output as if the virtual image speaks.
There are various virtual images, for example, an image of a virtual character related to a captured image, or a pre-captured person or landscape. Information on a virtual image or a sound output to the portable terminal is acquired from a storage section of the portable terminal or a server connected to the portable terminal through a network.
Also, as an example of related art that discloses the processing of generating and displaying an AR image, there is Patent Literature 1 (JP 2012-58838A).
However, the output of the virtual image or the sound is started with the recognition of the marker from the captured image as a trigger. Therefore, for example, when a user changes the direction of the imaging section (camera) of the portable terminal and thus the marker is deviated from the captured image, the output of the virtual image or sound is stopped.
When the user changes again the direction of the imaging section (camera) and thus the marker is put in the captured image, the output of the same virtual image or sound is played back from the beginning.
That is, the playback and stop of the virtual image are controlled by the following two processes.
(Processing 1) Starting the playback of the virtual image and the sound by the recognition of the marker from the captured image
(Processing 2) Ending the playback of the virtual image and the sound by the marker-lost from the captured image
For example, with regard to information in which content to be played back by marker recognition is made up of an about 30-second image and sound, a user will have to maintain a marker capturing state for 30 seconds, without moving a portable terminal, so as to view the whole 30-second content.
For example, if the marker is deviated from the captured image even once in 30 seconds, the playback of the content made up of the virtual image and sound is stopped on the way. Once again, if moving to the marker capturing position, the playback cannot be resumed from the stopped position and the playback is executed again from the start position of the content.
In such a situation, an example such as a place that is crowded with people coming and going, for example, a configuration that provides information to a user by setting a marker to a street advertisement, may make it difficult to transfer information to the user. That is, at a place that is crowded with people coming and going, a movement of a person is included in a captured image and it is difficult to allow a camera to continuously capture a marker. As a result, that occurs a problem that the playback is repeatedly executed from the start point of the content and it is difficult to play back the content to the end.